Clinical sensitivities of three different SARS-CoV RT-PCR assays

Sample originaMedian day of disease (range)bSensitivityc in confirmed patients as determined by various methods (target gene):
Artus kit (R)Roche kit (R)In-house (N)
Upper respiratory tractd10.5 (3-25)11/1910/18g11/19
Lower respiratory tracte12 (3-34)12/1212/1212/12
Stool12.5 (8-37)18/22g18/2320/23
Plasma9 (3-14)1/72/73/7
Otherf31 (2-54)4/51/43/5
  • a n = 66 samples. The samples were from 29 laboratory-confirmed SARS patients (25 patients with seroconversion in an immunofluorescence assay and 4 patients with a positive RT-PCR result in three independent assays [equivalent to World Health Organization criteria for laboratory confirmation of SARS]).

  • b That is, the day at which the sample was obtained.

  • c Expressed as the number of positive samples/total number of samples. The total percent sensitivities (95% confidence intervals) for the Artus, Roche, and in-house methods were 70.8% (59 to 82%), 67.1% (55 to 79%), and 74.2% (63 to 85%), respectively.

  • d Three saliva samples and sixteen nasopharyngeal swabs.

  • e Eight sputum samples, two endotracheal aspirate specimens, and two bronchoalveolar lavage samples.

  • f One jejunectomy sample, one dialysis fluid specimen, and three urine samples.

  • g There was no result for one sample due to a failed internal control. The sample was therefore omitted from the sensitivity evaluation for this assay.